This invention relates generally to the field of diesel engines, and more particularly to an apparatus for starting a large diesel engine in a railroad locomotive.
Modern locomotive engines are generally powered by a large diesel engine. For example, the assignee of the present invention provides diesel locomotives having a sixteen cylinder diesel engine, producing a peak power output in the range of 4,500 horsepower.
The initial starting of a cold diesel engine can be a difficult task, especially when the engine is large and is exposed to reduced ambient temperatures. Railroad locomotives incorporate large battery systems to provide power for an electric starter motor used to initiate the rotation of the diesel engine. Because diesel combustion depends upon the compression of the fuel within the cylinders of the engine to produce the necessary heat for combustion of the fuel, it is known to begin the supply of fuel to a large diesel engine only after the starter motor has raised the speed of the diesel engine to above a predetermined value. For example, many of the diesel locomotives supplied by the assignee of the present invention are equipped with a Bryce.RTM. fuel injection system provided by Lucas Industries Public Limited of the United Kingdom. The Bryce fuel injection system is designed to begin supplying fuel to the diesel engine only after the cranking speed of the engine has exceeded 90 revolutions per minute (RPM). While this design works well in most applications, there are occasions when it is extremely difficult to spin the diesel engine to 90 RPM with the starter motor. Such difficulties have been known to occur in very cold weather conditions and when one or more of the starter batteries is in a conditions and when one or more of the starter batteries is in a weakened condition. Should the starter motor be unable to achieve a cranking speed of 90 RPM in the diesel engine, the engine will not start because no fuel will be provided by the fuel injection system. The Bryce fuel injection system currently installed on many of the locomotive engines supplied by the assignee of this invention is not designed to permit the setpoint of 90 RPM to be changed. Therefore, there is little that the locomotive operator can do to start the diesel engine in the event that the starter motor fails to achieve the required engine cranking speed.